The present invention relates to a tunnel structure and rear heat exchanger for a snowmobile. The driving system for a snowmobile, e.g. an endless track, is accommodated within a structure known as a tunnel, which has a top wall and sidewalls. Endless tracks for snowmobiles often are provided with longitudinal rows of studs that protrude from the surface of the endless track and provide improved traction. In order to prevent damage to the snowmobile from the studs, sufficient clearance needs to be provided.
In addition, snowmobiles often are powered by liquid cooled engines. It would be desirable to improve the cooling capacity of the cooling system for a snowmobile engine.